Agree that she needs a break. But after half term think about putting her in control of when she does 11+ practice. When my DS was feeling like this I got a diary and asked him to choose when he did his work. So he knew he had to do Maths, English and VR, so he might choose Wednesday straight after school for Maths, Tuesday after dinner for English. Saturday first thing for VR etc. Once that was in the diary that was decided and the rest of the time we didn't mention the 11+. This meant that I wasn't spending every afternoon/evening trying to persuade him (nagging him
) which was part of what was making him so fed up with the whole thing. As parents it's frustrating when you know that can do well, but they wont put the work in. But it can end up in a vicious circle where the more frustrated you get, the more demotivated they get!
Try to give her lots of fun things to do. And bribes work wonders! (I paid DS 20p per paper with a 1p bonus for every mark he increased